Replenisher, surface-treated metallic material, and production method thereof

ABSTRACT

The purpose of the present invention is to provide a replenisher that avoids an increase in the HF concentration in a surface-treatment liquid for metal materials, is capable of supplying zirconium ions at high concentration by using the metal material surface-treatment liquid, and has excellent long-term storage stability, in order to continuously chemically convert and/or electrolytically treat a metal material. This replenisher contains prescribed amounts of: a zirconium compound not containing fluorine and including at least one type selected from a group comprising zirconium basic carbonate, zirconium carbonate, zirconium hydroxide, and ammonium zirconium carbonate; a fluorine-containing matter including at least one type selected from a group comprising hydrofluoric acid, a hydrofluoric acid salt, fluorozirconic acid, and a fluorozirconic acid salt; and an acid component including at least one type selected from a group comprising nitric acid, hydrochloric acid, sulfuric acid, and acetic acid.

TECHNICAL FIELD

The present invention relates to a replenisher, a surface-treatedmetallic material and a method for producing the same.

BACKGROUND ART

In order to impart functions, such as paint adhesion, corrosionresistance after painting and unpainted corrosion resistance, tometallic material products, a surface thereof is normally subjected to achemical conversion treatment including phosphate treatment and chromatetreatment depending on its application.

Recently, however, interests in reducing environmental loads have beenincreasing, and studies for reducing industrial wastes such as phosphatesludge have been conducted and the compliance with regulations on therestriction of the use of hexavalent chromium have been taken, and achemical conversion coating using a zirconium compound and the like isproposed as a new coating treatment to replace the phosphate treatmentor the chromate treatment (Patent Literature 1 and Patent Literature 2).More specifically, by performing chemical conversion treatment and/orelectrolysis treatment (for example, cathodic electrolysis and the like)on/over a metallic material in metallic material surface treatingsolution containing zirconium (hereinafter, also referred to as Zr) ionand fluorine (hereinafter, also referred to as F) ion, a zirconium-basedchemical conversion coating (hereinafter, also referred to simply ascoating) can be formed on/over the surface of the metallic material,thereby imparting excellent performance to the surface of the metallicmaterial.

When coatings are continuously produced through the above-describedsurface treatment for metallic materials, zirconium ion in the metallicmaterial surface treating solution is consumed while being convertedinto oxides and deposited as the coatings, whereby the zirconium ionconcentration in the metallic material surface treating solutiongradually decreases. In the meantime, an amount of fluorine ion that istaken into the coatings is smaller than that of zirconium ion so that adecrease in the fluorine ion concentration in the metallic materialsurface treating solution per unit area is smaller than that of thezirconium ion concentration.

More specifically, H₂ZrF₆ is often used in the metallic material surfacetreating solution containing zirconium ion, and the reaction formulathereof is as shown below.

H₂ZrF₆+2H₂O->ZrO₂↓+6HF  Formula (1)

At the interface between a metallic material and the metallic materialsurface treating solution, acid consumption due to etching, reduction ofhydrogen ion near a cathode electrode and the like raise the pH near themetallic material, hydrolysis of H₂ZrF₆ is caused as indicated byFormula (1), and a zirconium-based coating includes zirconium oxide orthe like is formed on/over the surface of the metallic material.

Regarding fluorine ion, on the other hand, as shown in Formula (1),generation of one mole of ZrO₂ theoretically causes 6 moles of HF to beproduced as a by-product in the metallic material surface treatingsolution. Compared to Zr that is the main component of the coating, theamount of HF taken into the coating is so small that, when metallicsurface treatment is continuously performed, HF accumulates in themetallic material surface treating solution, increasing theconcentration thereof. Since HF is shown in the right side of theFormula (1), if the HF concentration increases, the reaction to generatecoating is inhibited, making it difficult to properly produce coating ofthe zirconium compound. In addition, when the zirconium ionconcentration decreases, zirconium ion needs to be supplied. For thatpurpose, H₂ZrF₆ is normally supplied, but because of this ratio betweenzirconium ion and fluorine ion, accumulation of HF cannot be inhibited.Accordingly, in order to inhibit accumulation of HF, the method in whichpart of the metallic material surface treating solution is automaticallydrained (auto-drained) during continuous operation to keep the HFconcentration constant has been conventionally adopted in many cases.However, in the environmental and economical point of view, it is notpreferable to auto-drain the solution containing a large amount ofzirconium ion or HF into drainage water in spite of the fact that thecoatings with reduced environmental loads have been proposed, and thusimprovements are desired.

Accordingly, Patent Literature 3 proposes that the above-describedproblem can be solved by replenishing the metallic material surfacetreating solution with zirconium ion in such an amount that the balancewith the amount of supplied fluorine ion is taken into considerationusing a replenisher containing a fluorine-containing zirconium compoundand a fluorine-free zirconium compound. In particular, Patent Literature3 discloses in paragraph [0033] that replenishment of Zr ion wasperformed by using a mixed solution of hexafluorozirconic acid andzirconium nitrate (weight ratio of hexafluorozirconic acid:zirconiumnitrate=55:45) having the Zr ion concentration of 17 g/L.

CITATION LIST Patent Literature

[Patent Literature 1] JP 2008-202149 A

[Patent Literature 2] JP 2010-90407 A

[Patent Literature 3] JP 4996409 B

SUMMARY OF INVENTION Technical Problems

Meanwhile, a replenisher used to replenish the metallic material surfacetreating solution with zirconium ion is usually stored for a long timein a storehouse or the like after purchase. Hence, the replenisher hasto be in a usable condition after a long-term storage. In particular, itis required that, when the replenisher is stored in the high-temperatureenvironment for a long period of time, precipitation or the like notoccur in the replenisher.

The inventors of the present invention studied storage stability of thereplenisher specifically described in Patent Literature 3 and found thatthe storage stability thereof was not at the recent satisfactory level,and further improvements were necessary.

Moreover, in the recent years, cost reduction for the coating treatmentis desired, and therefore further improvements in the productionefficiency of the coating treatment are desired. Examples of the methodto improve the production efficiency include the method in whichauto-drainage is suppressed as much as possible, and the method in whichthe coating treatment is performed while the accumulated treatment loadis increased to be larger compared to the conventional method. Theaccumulated treatment load refers to a value (S/V(m²/L)) obtained bydividing the accumulated treatment area (Sm²) of a metallic material bythe volume (VL) of the metallic material surface treating solution asthe result of continuous operation of the coating treatment. For thetechnique of coating treatment for the metallic material, it isnecessary that variation in the composition balance of the metallicmaterial surface treating solution be small with respect to the largeraccumulated treatment load, and that the treatment performance notdegrade. If the variation in the composition balance of the metallicmaterial surface treating solution is large with respect to theaccumulated treatment load, or the treatment performance easilydegrades, the metallic material surface treating solution has to bepartially or wholly renewed to keep the stable treatment performance.Such case is not preferable from the standpoints of the productionefficiency, costs and the environment.

The present inventors performed continuous operation of coatingtreatment using the replenisher specifically described in PatentLiterature 3, studied the coating treatment performance when theaccumulated treatment load is larger, and discovered that the coatingweight on/over the metallic material would have decreased.

Under the above-described circumstances, an object of the presentinvention is to provide a replenisher that can replenish the metallicmaterial surface treating solution with zirconium ion at the higherconcentration while inhibiting an increase of the HF concentration inthe metallic material surface treating solution such that chemicalconversion treatment and/or electrolysis treatment can be continuouslyperformed on/over metallic materials, and that exhibits excellentlong-term storage stability.

In addition, an object of the present invention also is to provide amethod for producing a surface-treated metallic material using thereplenisher.

Solution to Problems

As a result of the intense study, the present inventors discovered thatthe above-described problem can be solved by using a replenisher withhigh zirconium ion concentration that is obtained by using thepredetermined compound.

That is, the constitution of the present invention to solve theabove-described problem is described below.

(1) A replenisher used to replenish metallic material surface treatingsolution with zirconium ion, the metallic material surface treatingsolution containing zirconium ion and fluorine ion and being used toform a chemical conversion coating containing zirconium on/over ametallic material through chemical conversion treatment and/orelectrolysis treatment, the replenisher comprising:

a fluorine-free zirconium compound (A) containing at least one selectedfrom a group consisting of zirconium basic carbonate, zirconiumcarbonate, zirconium hydroxide and ammonium zirconium carbonate; afluorine-containing compound (B) containing at least one selected fromthe group consisting of hydrofluoric acid, a salt of hydrofluoric acid,hexafluorozirconic acid and a salt of hexafluorozirconic acid; and anacid component (C) containing at least one selected from the groupconsisting of nitric acid, hydrochloric acid, sulfuric acid and aceticacid,

wherein following relationships (I) to (III) are satisfied:

(I) a ratio (M_(AC)/M_(F)) of a total molar quantity (M_(AC)) of anionsderived from the acid component (C) with respect to a total molarquantity (M_(F)) of fluorine ion derived from the fluorine-containingcompound (B) is 0.35 or more and less than 2.00;(II) a total concentration (g/L) of zirconium ion derived from thefluorine-free zirconium compound (A) and the fluorine-containingcompound (B) is 25 or higher; and(III) a ratio (M_(F)/F_(Zr)) of a total molar quantity (M_(F)) offluorine ion derived from the fluorine-containing compound (B) withrespect to a total molar quantity (M_(Zr)) of zirconium ion derived fromthe fluorine-free zirconium compound (A) and the fluorine-containingcompound (B) is 2.00 or more and less than 6.00.(2) The replenisher according to (1), wherein the ratio (M_(AC)/M_(F))exceeds 0.50 and is less than 2.00.(3) The replenisher according to (1) or (2), wherein the ratio(M_(AC)/M_(F)) exceeds 0.50 and is 1.60 or less.(4) A method for producing a surface-treated metallic materialcomprising:

continuously performing chemical conversion treatment and/orelectrolysis treatment on/over a metallic material in metallic materialsurface treating solution containing zirconium ion and fluorine ion toform a chemical conversion coating containing zirconium on/over themetallic material; and

replenishing the metallic material surface treating solution withzirconium ion by adding the replenisher according to any one of (1) to(3) to the metallic material surface treating solution.

(5) A surface-treated metallic material obtained by the method forproducing a surface-treated metallic material according to (4).

Advantageous Effects of Invention

The present invention can provide a replenisher having more excellentlong-term storage stability and capable of replenishing the metallicmaterial surface treating solution with zirconium ion at highconcentration while the HF concentration in the metallic materialsurface treating solution is inhibited from increasing such thatchemical conversion treatment and/or electrolysis treatment can becontinuously performed on/over metallic materials.

In addition, according to the present invention, the method forproducing a surface-treated metallic material using the replenisher canbe provided.

DESCRIPTION OF EMBODIMENTS

Below, the replenisher and the method for producing a surface-treatedmetallic material of the present invention are described.

The replenisher of the present invention contains a predeterminedfluorine-free zirconium compound (A), a predeterminedfluorine-containing compound (B) and a predetermined acid component (C),and contains zirconium ion (Zr ion) at a high concentration. Of thereplenisher of the present invention, a ratio (M_(AC)/M_(F)) between thetotal molar quantity (M_(AC)) of anions derived from the acid component(C) and the total molar quantity (M_(F)) of fluorine ion (F ion), and aratio (M_(F)M_(Zr)) between the total molar quantity (M_(Zr)) ofzirconium ion and the total molar quantity (M_(F)) of fluorine ion fallwithin predetermined ranges. By satisfying the components and thecomponent quantity ratios above, the replenisher can achieve long-termstorage stability. Moreover, the replenisher contains zirconium ion atthe higher concentration compared to fluorine ion. Accordingly, when themetallic material surface treating solution is continuously replenishedwith the replenisher in continuous production of chemical conversioncoatings, increase of HF can be inhibited and a large amount ofzirconium ion can be continuously supplied. As a result, the chemicalconversion treatment and/or electrolysis treatment can be continuouslyperformed on/over metallic materials while the amount of auto-drainedsolution is suppressed. Specifically, by adjusting the ratio(M_(AC)/M_(F)) to fall within the predetermined range, the replenisherthat has more excellent long-term storage stability and that enables thechemical conversion treatment and/or electrolysis treatment to becontinuously performed on/over metallic materials can be provided.

An aspect of the replenisher of the present invention is first describedbelow, and the method for producing a surface-treated metallic materialusing the replenisher is then described.

[Replenisher]

The replenisher of the present invention is used to mainly supplyzirconium ion to a metallic material surface treating solution thatcontains zirconium ion and fluorine ion and that is used to form on/overa metallic material surface a chemical conversion coating containingzirconium as the main component through chemical conversion treatmentand/or electrolysis treatment. Meanwhile, it should be noted thatimplementation of auto-drainage in the continuous production of chemicalconversion coatings is not denied.

First, respective materials contained in the replenisher are describedin detail, and the method for producing the replenisher is thendescribed in detail.

(Fluorine-Free Zirconium Compound (A))

The fluorine-free zirconium compound (A) contained in the replenisher ofthe present invention is a compound that does not contain fluorine atomsbut contains Zr atoms.

The fluorine-free zirconium compound (A) includes at least one compoundselected from the group consisting of zirconium basic carbonate,zirconium carbonate, zirconium hydroxide and ammonium zirconiumcarbonate. Among these, zirconium basic carbonate or zirconium carbonateis more preferable in terms of improving the storage stability of thereplenisher and continuously performing the surface treatment morefrequently (hereinafter, simply referred to as “in terms of improvingthe excellent effect of the present invention”).

Two or more compounds described above may be used as the fluorine-freezirconium compound (A).

(Fluorine-containing Compound (B))

The fluorine-containing compound (B) contained in the replenisher of thepresent invention is a compound that contains fluorine atoms and thatsupplies the replenisher with F ion. When hexafluorozirconic acid or asalt thereof is used as the fluorine-containing compound (B), Zr ion isalso supplied into the replenisher.

The fluorine-containing compound (B) includes at least one compoundselected from the group consisting of hydrofluoric acid, a salt ofhydrofluoric acid, hexafluorozirconic acid and a salt ofhexafluorozirconic acid. Among these, hydrofluoric acid orhexafluorozirconic acid is more preferable from the standpoint ofimproving the excellent effect of the present invention.

Examples of the salt of hydrofluoric acid includes a salt ofhydrofluoric acid with a base (such as an amine compound) and preferablya salt of hydrofluoric acid with a base that contains no metal, such asan ammonium salt. Furthermore, examples of the salt ofhexafluorozirconic acid include metal acid salts (for example, sodiumsalt, potassium salt, lithium salt, ammonium salt and the like) such asK₂ZrF₆.

Two or more compounds described above may be used as thefluorine-containing compound (B).

(Acid Component (C))

The acid component (C) contained in the replenisher of the presentinvention performs roles as adjusting a pH of the replenisher andpromoting solubility of other components (fluorine-free zirconiumcompound (A) and/or fluorine-containing compound (B)).

The acid component (C) includes at least one component selected from thegroup consisting of nitric acid, hydrochloric acid, sulfuric acid andacetic acid. Among these, nitric acid or sulfuric acid is morepreferable from the standpoint of improving the excellent effect of thepresent invention.

Two or more acid components described above may be used as the acidcomponent (C).

(Respective Component Contents)

The respective components in the replenisher of the present inventionsatisfy the following relationships (I) to (III).

(I) The ratio (M_(AC)/M_(F)) of the total molar quantity (M_(AC)) ofanions derived from the acid component (C) with respect to the totalmolar quantity (M_(F)) of fluorine ion derived from thefluorine-containing compound (B) is 0.35 or more and less than 2.00.(II) The total concentration (g/L) of zirconium ion derived from thefluorine-free zirconium compound (A) and the fluorine-containingcompound (B) is 25 or higher.(III) The ratio (M_(F)/M_(Zr)) of the total molar quantity (M_(F)) offluorine ion derived from the fluorine-containing compound (B) withrespect to the total molar quantity (M_(Zr)) of zirconium ion derivedfrom the fluorine-free zirconium compound (A) and thefluorine-containing compound (B) is 2.00 or more and less than 6.00.

The relationships are independently described below.

(Relationship (I))

In the replenisher of the present invention, the ratio (M_(AC)/M_(F)) ofthe total molar quantity (M_(AC)) of anions derived from the acidcomponent (C) with respect to the total molar quantity (M_(F)) offluorine ion derived from the fluorine-containing compound (B) is 0.35or more and less than 2.00. When the ratio is within this range, thereplenisher has excellent storage stability and enables continuous andstable production of chemical conversion coatings without accumulationof HF in the metallic material surface treating solution. As the rangefor the more excellent effect of the present invention, the ratio(M_(AC)/M_(F)) is preferably more than 0.40 and less than 2.00, morepreferably more than 0.50 and less than 2.00, further more preferablymore than 0.50 and 1.60 or less, and yet further more preferably 1.00 ormore and 1.60 or less.

When the ratio (M_(AC)/M_(F)) is less than 0.35, the long-term storagestability of the replenisher is inferior. If the ratio (M_(AC)/M_(F)) is2.00 or more, when the replenisher is continuously used, the coatingweight would decrease, and the desired coating cannot be formed.

Anions derived from the acid component (C) (nitric acid, hydrochloricacid, sulfuric acid and acetic acid) are NO₃ ⁻, SO₄ ²⁻, and CH₃COO⁻.

(Relationship (II))

In the replenisher of the present invention, the total concentration(g/L) of zirconium ion derived from the fluorine-free zirconium compound(A) and from the fluorine-containing compound (B) is 25 or higher. Whenthe concentration is within the range, chemical conversion coatings canbe more economically produced. Particularly, the total concentration(g/L) of zirconium ion is preferably 30 or higher, and more preferably35 or higher, since the amount of replenisher used can be reduced, andthe operation economy can be better. Although not particularly limitedthereto, the upper limit of the concentration is often 70 or lower, inview of solubility of the fluorine-free zirconium compound (A) and thefluorine-containing compound (B).

When the total concentration (g/L) of zirconium ion is lower than 25,since the replenisher is dilute, a large amount of the replenisher needsto be supplied to the metallic material surface treating solution andthus causes an excessive replenishment, whereby the amount of themetallic material surface treating solution increases. As a result, inorder to continuously perform the chemical conversion treatment, it isrequired to increase the auto-drainage amount of the metallic materialsurface treating solution, which is not preferable from theenvironmental and economical standpoint.

In addition, when hexafluorozirconic acid or a salt thereof is used asthe fluorine-containing compound (B), zirconium ion derived from thefluorine-containing compound (B) are supplied.

(Relationship (III))

In the replenisher of the present invention, the ratio (M_(F)/M_(Zr)) ofthe total molar quantity (M_(F)) of fluorine ion derived from thefluorine-containing compound (B) with respect to the total molarquantity (M_(Zr)) of zirconium ion derived from the fluorine-freezirconium compound (A) and the fluorine-containing compound (B) is 2.00or more and less than 6.00. When the ratio is within this range, stableproduction of chemical conversion coatings can be continuously performedwithout accumulation of HF in the metallic material surface treatingsolution. As the range for the more excellent effect of the presentinvention, the ratio (M_(F)/M_(Zr)) is preferably 2.50 to 5.50, and morepreferably 3.00 to 5.00.

When the ratio (M_(F)/M_(Zr)) is less than 2.00, it is difficult to havezirconium compounds dissolved in the replenisher. In addition, if theratio (M_(F)/M_(Zr)) is 6.00 or more, when the replenisher iscontinuously used, accumulation of HF in the metallic material surfacetreating solution cannot be inhibited. Therefore, for stable productionof chemical conversion coatings, the amount of auto-drained solutionneeds to be increased, which is not preferable from the environmentaland economical standpoint.

The respective ions described above can be measured using a knownmeasurement device, atomic absorption, ICP, ion chromatography, or afluorine ion meter.

In the replenisher of the present invention, the fluorine-free zirconiumcompound (A) content is not particularly limited as long as theabove-described relationships (I) to (III) are satisfied, but ispreferably 0.1 to 500 parts by mass, and more preferably 10 to 300 partsby mass, with respect to 100 parts by mass of the fluorine-containingcompound (B), since the deposition efficiency of the chemical conversioncoating is excellent.

The pH of the replenisher of the present invention is not particularlylimited, but is preferably less than 4.0, and more preferably more than0 and 1.5 or less, since the replenisher has excellent stability. Whenthe pH is adjusted, an alkaline component can be also used. The alkalinecomponent include alkali metal oxides such as sodium hydroxide,potassium hydroxide and the like; hydroxides of alkali earth metals suchas calcium hydroxide, magnesium hydroxide and the like; and organicamines such as ammonia, monoethanolamine, diethanolamine,triethanolamine and the like. Among these, ammonia is preferably usedsince it has no metallic contamination and contains no organic solvent.

The replenisher of the present invention may contain a solvent asnecessary. The type of solvent used is not particularly limited, andwater and/or an organic solvent is normally used.

Examples of the organic solvent include an alcohol-based solvent and thelike. While the organic solvent content may be within the range in whichstability of the replenisher and of the metallic material surfacetreating solution to be replenished with the replenisher is notimpaired, no organic solvent is preferably contained from the standpointof the working environment.

The total mass of the above-described fluorine-free zirconium compound(A), fluorine-containing compound (B) and acid component (C) when thereplenisher contains a solvent is preferably 2 mass % to 90 mass %, andmore preferably 4 mass % to 80 mass %, with respect to the wholequantity of replenisher, since the deposition efficiency of the chemicalconversion coating is more excellent.

The method for producing the replenisher of the present invention is notparticularly limited, and any known method is adopted. Examples thereofinclude the method in which the fluorine-free zirconium compound (A),the fluorine-containing compound (B) and the acid component (C) areadded in the solvent(s) and mixed.

[Method for Producing Surface-Treated Metallic Materials]

Below described is the method for producing the surface-treated metallicmaterials using the replenisher of the present invention.

The method for producing the surface-treated metallic materials of thepresent invention is a method in which chemical conversion treatmentand/or electrolysis treatment is continuously performed on/over ametallic material in a metallic material surface treating solutioncontaining zirconium ion and fluorine ion to form a chemical conversioncoating containing zirconium on/over the metallic material.

When the method for producing the surface-treated metallic materialsdescribed above is continuously performed, the zirconium ionconcentration in the metallic material surface treating solutiondecreases accordingly, making it harder to form a coating containing azirconium compound. In order to compensate for the decrease in thezirconium ion concentration, the metallic material surface treatingsolution is replenished with the replenisher described above.

Generally, in order to obtain the predetermined chemical conversioncoatings on/over metallic materials continuously and stably, thereplenisher is preferably added to the metallic material surfacetreating solution in such a manner that the zirconium ion concentrationdoes not decrease by 20% or more. The total amount of fluorine ionsupplied together with zirconium is preferably an amount obtained bysubtracting the amount of fluorine ion in HF generated in the metallicmaterial surface treating solution as a by-product during producing thecoating containing the zirconium compound from the sum of all fluorineion that is taken into the chemical conversion coating and all fluorineion in the metallic material surface treating solution that adheres tothe metallic material having the chemical conversion coating formedon/over the surface when the metallic material is taken out from thebath.

The method for adding the replenisher of the present invention into themetallic material surface treating solution is not particularly limited,and examples thereof include the method in which the replenisher isdivided into small portions and added in several times (method A) andthe method in which the replenisher in a predetermined amount is addedat once (method B). Particularly, the method A is preferable, sincecomponent variation in the metallic material surface treating solutionis small and the surface-treated metallic materials can be continuouslyand stably produced.

In addition, when the replenisher of the present invention is added intothe metallic material surface treating solution, either of the method inwhich production is once suspended and the replenisher is added into themetallic material surface treating solution and the method in whichproduction is not suspended and the replenisher is added into themetallic material surface treating solution during production method ofthe surface-treated metallic materials can be adopted. Of these, themethod in which the replenisher is added into the metallic materialsurface treating solution during production method of thesurface-treated metallic materials is preferable, since productionefficiency is excellent particularly at high-speed operation, and thesurface-treated metallic materials can be continuously and stablyproduced.

Below, the metallic material surface treating solution used in themethod for producing the surface-treated metallic materials of thepresent invention is described.

(Metallic Material Surface Treating Solution)

The metallic material surface treating solution used in the method forproducing the surface-treated metallic materials of the presentinvention described above contains Zr ion and fluorine ion.

Examples of the supply source of zirconium ion in the metallic materialsurface treating solution include the above-described fluorine-freezirconium compound (A), hexafluorozirconic acid or a salt thereof.

Zr ion in the metallic material surface treating solution refers to both(1) zirconium fluoride complex ion in which 1 to 6 moles of fluorine arecoordinated to 1 mole of zirconium as expressed by ZrF_(n) ^((4-n)) and(2) zirconium ion or zirconyl ion generated from inorganic acidzirconium such as zirconium nitrate and zirconium sulfate or inorganicacid zirconyl, or alternatively, an organic acid zirconium or organicacid zirconyl such as zirconium acetate and zirconyl acetate.

The amount of zirconium ion contained in the metallic material surfacetreating solution is not particularly limited but is preferably 0.05 g/Lto 10.00 g/L, and more preferably 0.10 g/L to 2.00 g/L, since themetallic material surface treating solution has more excellentstability, and the deposition efficiency of the chemical conversioncoating is also more excellent.

Any known compound containing fluorine (fluorine-containing compound)can be used as the supply source of fluorine ion in the metallicmaterial surface treating solution.

A fluorine compound having at least one element selected from the groupconsisting of Ti, Zr, Hf, Si, Al and B is preferably used as thefluorine-containing compound. Specific examples thereof includecomplexes in which 1 to 3 hydrogen atoms are coordinated to anions suchas (TiF₆)²⁻, (ZrF₆)²⁻, (HfF₆)²⁻, (SiF₆)²⁻, (AlF₆)³⁻ and (BF₄OH)⁻, andammonium salts and metal salts of these anions.

Other examples of the fluorine-containing compound include hydrofluoricacid and its ammonium salt and alkali metal salts; metal fluorides (suchas aluminum fluoride, zinc fluoride, vanadium fluoride, tin fluoride,manganese fluoride, ferrous fluoride and ferric fluoride or the like);and acid fluorides (such as fluorine oxide, acetyl fluoride and benzoylfluoride or the like).

Fluorine ion in the metallic material surface treating solution refersto both fluorine ion (F⁻) derived from HF present in the metallicmaterial surface treating solution and fluorine ion influorine-containing complex ion such as the above-described zirconiumfluoride complex ion, and the total fluorine ion concentration describedabove and later refers to the concentration of the sum of both fluorineion. Free fluorine concentration refers to the concentration ofHF-derived fluorine ion (F⁻).

The total amount of fluorine ion contained in the metallic materialsurface treating solution is not particularly limited but is preferably0.050 g/L to 10.000 g/L, and more preferably 0.100 g/L to 3.000 g/L asthe total fluorine ion concentration, since the metallic materialsurface treating solution has more excellent stability, and thedeposition efficiency of the chemical conversion coating is alsoexcellent. The free fluorine ion concentration is preferably 5 mg/L to400 mg/L, and more preferably 10 mg/L to 250 mg/L.

The amounts (concentrations) of Zr ion, total fluorine ion, and freefluorine ion in the metallic material surface treating solution can bemeasured by using atomic absorption, ICP, ion chromatography or afluorine ion meter.

The pH of the metallic material surface treating solution isappropriately adjusted according to the metallic material to be treatedor the condition of the chemical conversion treatment or electrolysistreatment, but is preferably about 2.5 to 5.0, and more preferably 3.0to 5.0, since the metallic material surface treating solution has moreexcellent stability and the deposition efficiency of the chemicalconversion coating is also more excellent. The pH of the metallicmaterial surface treating solution can be measured by using a pH meter.

Below described are the metallic material used in the method forproducing the surface-treated metallic material of the present inventionas well as the chemical conversion treatment and the electrolysistreatment.

(Metallic Material)

The type of metallic material used is not particularly limited, and anyknown metallic material can be used. Examples thereof include ironmaterial, plating material, zinc material, aluminum material, magnesiummaterial and the like.

The shape of the metallic material is not particularly limited and canbe a plate shape or any other shape. Examples of the other shapesinclude a vehicle body of a transporting device such as an automobileand its constituent component, a farm equipment and its constituentcomponent, steel furniture, building material and the like.

(Chemical Conversion Treatment or Electrolysis Treatment)

The chemical conversion treatment using the metallic material surfacetreating solution described above can be performed using known treatmentfacilities under a known condition. The chemical conversion treatment isa treatment in which a metallic material is brought into contact(immersion, coating or spraying) with a predetermined metallic materialsurface treating solution that is at normal temperature or heated,whereby a coating is formed on/over the surface of the metallicmaterial.

The duration of contact between the metallic material and the metallicmaterial surface treating solution is appropriately adjusted dependingon the quality or shape of the metallic material to be treated,treatment method, application thereof and the targeted coating weight,and is normally about 0.1 second to 600 seconds in many cases, since thechemical conversion coating has more excellent properties.

The electrolysis treatment (anodic electrolysis treatment, cathodicelectrolysis treatment) using the metallic material surface treatingsolution can be performed using known electrolysis treatment facilitiesunder a known condition.

For example, the current density is preferably 0.1 A/dm² to 20.0 A/dm²,and more preferably 0.5 A/dm² to 10.0 A/dm² since the depositionefficiency of the chemical conversion coating is excellent.

The coating weight of zirconium in the formed chemical conversioncoating is appropriately adjusted depending on the quality orapplication of the metallic material to be treated, and is normallyabout 1 mg/m² to 70 mg/m² in many cases in both the chemical conversiontreatment and the electrolysis treatment, since the chemical conversioncoating has more excellent properties.

EXAMPLES

The present invention is illustrated below with specific examples. Theexamples are given merely by way of illustration of the presentinvention and should not be construed as limiting the invention.

(Test Sheet)

The following test sheets (1) to (3) were used in Examples andComparative Examples.

(1) Aluminum alloy sheet (6000-series aluminum alloy, thickness: 0.8 mm)(2) Cold-rolled steel sheet (SPC, thickness: 0.8 mm)(3) Alloyed hot-dip galvanized steel sheet (GA, thickness: 0.8 mm)

(Replenisher)

The fluorine-free zirconium compound (A), the fluorine-containingcompound (B) and the acid component (C) were mixed in water so as tohave compositions shown in Table 1, whereby the various replenisherswere prepared.

(Surface Treatment Methods for Metallic Materials)

The surface treatment methods for metallic materials in Examples andComparative Examples described below were performed in accordance withthe following procedure.

(1) Degreasing

(2) Washing with water (tap water)(3) Chemical conversion treatment(4) Washing with water (tap water)(5) Washing with water (ion-exchanged water)(6) Draining off water and drying

The above degreasing process was performed using an alkaline degreasingagent, Finecleaner L4460 (2.0%; 45° C., 120 seconds, spraying)manufactured by Nihon Parkerizing Co., Ltd.

The chemical conversion treatment method will be described in detail inthe next section about the continuous treating test method. In addition,in the process of draining off water and drying, after draining off thewater with rollers, drying was performed in an oven at 100° C.

(Continuous Treating Test Method (Running Test))

As the above-described chemical conversion treatment, any one of thefollowing continuous treating methods 1 to 3 was performed.

<Continuous Treating Method 1>

After a bath was made up of 10 L of treating solution having thecomponents of concentrations described below, the treating solution wasadjusted to have a pH of 4.0 and heated to 40° C. to prepare a metallicmaterial surface treating solution. The metallic material surfacetreating solution was stirred and a test sheet (1) was immersed in themetallic material surface treating solution for 180 seconds, whereby thesurface treatment was performed to achieve a target Zr coating weight of13 mg/m². This process was regarded as one cycle and repeated using newtest sheets (1) so as to perform surface treatment (continuous treatingtest). In this process, since the amount of the metallic materialsurface treating solution that adhered to and was taken out by the testsheet (1) (taken-out solution) was 75 mL/m², water and the replenishershown in Table 1 were added to restore the solution level and toreplenish the decreased Zr concentration in the metallic materialsurface treating solution at every processing load of 0.5 m²/L, therebyadjusting the solution level and the Zr concentration at a time. The pHof the metallic material surface treating solution was also adjusted atevery 0.5 m²/L with ammonia water as necessary. The above-describedcontinuous treating test was performed until 100% of all treatingsolution of 10 L was replaced as the taken-out solution. That is, thetest was conducted until the processing load reached 13.3 m²/L, and theZr coating weight at the beginning of the continuous treating test andthe Zr coating weight at the time when the processing load became 13.3m²/L were measured. The Zr coating weight on the surface of the treatedmaterial was quantitatively determined using X-ray fluorescence (XRF)analysis.

(Components of Treating Solution)

Concentrations of the respective components were as follows: Zr ionconcentration was 100 mg/L, total F ion concentration was 150 mg/L, freeF ion concentration was 25 mg/L, and NO₃ ion concentration was 190 mg/L.

<Continuous Treating Method 2>

After a bath was made up of 10 L of a treating solution having thecomponents of concentrations described below, the treating solution wasadjusted to have a pH of 4.0 and heated to 40° C. to prepare a metallicmaterial surface treating solution. The metallic material surfacetreating solution was stirred and a test sheet (2) was immersed in themetallic material surface treating solution for 120 seconds, whereby thesurface treatment was performed to achieve a target Zr coating weight of20 mg/m². This process was regarded as one cycle and repeated using newtest sheets (2) so as to perform surface treatment (continuous treatingtest). In this process, since the amount of the metallic materialsurface treating solution that adhered to and was taken out by the testsheet (2) (taken-out solution) was 60 mL/m², water and the replenishershown in Table 1 were added to restore the solution level and toreplenish the decreased Zr concentration in the metallic materialsurface treating solution at every processing load of 0.5 m²/L, therebyadjusting the solution level and the Zr concentration at a time. The pHof the metallic material surface treating solution was also adjusted atevery 0.5 m²/L with ammonia water as necessary. The above-describedcontinuous treating test was performed until 100% of all treatingsolution of 10 L was replaced as the taken-out solution. That is, thetest was conducted until the processing load reached 16.7 m²/L, and theZr coating weight at the beginning of the continuous treating test andthe Zr coating weight at the time when the processing load became 16.7m²/L were measured. The Zr coating weight on the surface of the treatedmaterial was quantitatively determined using X-ray fluorescence (XRF)analysis.

(Components of Treating Solution)

Concentrations of the respective components were as follows: Zr ionconcentration was 500 mg/L, total F ion concentration was 680 mg/L, freeF ion concentration was 36 mg/L, and NO₃ ion concentration was 750 mg/L.

<Continuous Treating Method 3>

After a bath was made up of 10 L of treating solution having thecomponents of concentrations described below, the treating solution wasadjusted to have a pH of 3.7 and heated to 40° C. to prepare a metallicmaterial surface treating solution. The metallic material surfacetreating solution was stirred and a test sheet (3) was immersed in themetallic material surface treating solution for 30 seconds, thereby thesurface treatment was performed to achieve a target Zr coating weight of10 mg/m². This process was regarded as one cycle and repeated using newtest sheets (3) so as to perform surface treatment (continuous treatingtest). In this process, since the amount of the metallic materialsurface treating solution that adhered to and was taken out by the testsheet (3) (taken-out solution) was 22 mL/m², water and the replenishershown in Table 1 were added to restore the solution level and toreplenish the decreased Zr concentration in the metallic materialsurface treating solution at every processing load of 0.5 m²/L, therebyadjusting the solution level and the Zr concentration at a time. The pHof the metallic material surface treating solution was also adjusted atevery 0.5 m²/L with ammonia water as necessary. The above-describedcontinuous treating test was performed until 100% of all treatingsolution of 10 L was replaced as the taken-out solution. That is, thetest was conducted until the processing load reached 45.5 m²/L, and theZr coating weight at the beginning of the continuous treating test andthe Zr coating weight at the time when the processing load became 45.5m²/L were measured. The Zr coating weight on the surface of the treatedmaterial was quantitatively determined using X-ray fluorescence (XRF)analysis.

(Components of Treating Solution)

Concentrations of the respective components were as follows: Zr ionconcentration was 1,500 mg/L, total F ion concentration was 2,010 mg/L,free F ion concentration was 95 mg/L, and NO₃ ion concentration was2,190 mg/L.

(5) Evaluation Test

Evaluations (A) and (B) shown below were carried out by using thereplenisher shown in Table 1.

(A) Replenisher Storage Stability Test (Long-term Storability)

The replenisher shown in Table 1 was put in a plastic container, whichwas sealed. The replenisher was stored for a maximum of 6 months at 35°C. immediately after sealed, and appearance of the solution was thenevaluated. The evaluation standards are described below. Practically,“Good” or “Excellent” is preferable.

Excellent: Appearance does not change on or later than 6 months from thestart of storage.Good: Appearance changes in a period starting on or later than 3 monthsand ending earlier than 6 months from the start of storage.Fair: Appearance changes in a period starting on or later than 2 weeksand ending earlier than 3 months from the start of storage.Poor: Precipitation, or turbidness or gelation of the solution isobserved earlier than 2 weeks from the start of storage.

Here, “appearance does not change” means that none of precipitation,turbidness and gelation is observed, and the solution is colorless andtransparent.

(B) Running Test (Continuous Treating Test)

Continuous treating test was conducted according to the treating methodsshown in Table 1, the Zr coating weight on the test piece (test sheet)was determined at the beginning of the test (first cycle) and at thetime when the treating solution was 100% replaced, and the thusdetermined values were compared. The evaluation standards are describedbelow. Practically, “Good” or “Excellent” is preferable.

Excellent: The Zr coating weight after 100% replacement is 95% or moreand less than 105% with respect to the Zr coating weight at thebeginning of the continuous treating test.Good: The Zr coating weight after 100% replacement is 85% or more andless than 95% with respect to the Zr coating weight at the beginning ofthe continuous treating test.Fair: The Zr coating weight after 100% replacement is 50% or more andless than 85% with respect to the Zr coating weight at the beginning ofthe continuous treating test.Poor: The Zr coating weight after 100% replacement is less than 50% withrespect to the Zr coating weight at the beginning of the continuoustreating test.

TABLE 1 Replenisher Composition Con- Fluorine-free Performance tinuousZirconium Fluorine- Acid Zr Evaluation Treating Component containingComponent Concentration Long-term Running Method (A) Component (B) (C)g/L M_(F)/M_(Zr) M_(AC)/M_(F) Storability Property Example 1 1 Zr CarbHF Nitric Acid 35 3.00 1.00 Excellent Excellent Example 2 2 Zr Carb HFNitric Acid 35 4.00 0.50 Good Good Example 3 3 Zr Basic Carb H₂ZrF₆ + HF*1) Nitric Acid 45 5.00 0.50 Good Good Example 4 1 Zr Carb HF NitricAcid 25 3.00 1.20 Excellent Excellent Example 5 2 Zr Carb HF Nitric Acid35 4.00 1.20 Excellent Excellent Example 6 3 Zr Basic Carb HF NitricAcid 35 5.00 1.20 Excellent Excellent Example 7 1 Zr Carb HF Nitric Acid25 3.00 1.80 Excellent Good Example 8 2 Zr Carb HF Nitric Acid 35 4.001.80 Excellent Good Example 9 3 Zr Basic Carb H₂ZrF₆ + HF *1) NitricAcid 28 5.00 1.80 Excellent Good Comparative Example 1 1 Zr Carb HFNitric Acid 25 3.00 0.33 Poor *2) Comparative Example 2 2 Zr Basic CarbHF Nitric Acid 35 4.00 0.33 Poor *2) Comparative Example 3 3 Zr BasicCarb H₂ZrF₆ + HF *1) Nitric Acid 45 5.00 0.33 Poor *2) ComparativeExample 4 1 Zr Carb HF Nitric Acid 25 3.00 2.50 Good Poor ComparativeExample 5 2 Zr Basic Carb HF Nitric Acid 35 4.00 2.50 Good FairComparative Example 6 3 Zr Basic Carb H₂ZrF₆ + HF *1) Nitric Acid 305.00 2.50 Good Fair In Table 1, “Zr Carb” refers to zirconium carbonate,“Zr Basic Carb” refers to zirconium basic carbonate, and “ZrConcentration” refers to zirconium ion concentration (g/L). *1)H₂ZrF₆:HF = 4.6:1 (weight ratio) *2) In Comparative Examples 1 to 3,since the replenisher had so poor long-term storability thatprecipitation was observed within 1 week at 35° C., the replenisher wasregarded as practically unusable, and thus the running test was notperformed.

As shown in Table 1, in Examples where the replenisher of the presentinvention was used, it was confirmed that the replenisher had excellentlong-term storability as well as excellent continuous treatingproperties (continuous operation properties).

Particularly, as is seen from the comparison of Examples 2 to 3 withExamples 1 and 4 to 9, it was confirmed that when M_(AC)/M_(F) exceeded0.50 and was less than 2.00, the replenisher had more excellentlong-term storability.

In addition, as is seen from the comparison of Examples 2 to 3 and 7 to9 with Examples 1 and 4 to 6, it was confirmed that when M_(AC)/M_(F)exceeded 0.50 and was 1.60 or less, running property (continuousoperation property) was more excellent.

On the other hand, in Comparative Examples 1 to 3 where the ratio(M_(AC)/M_(F)) is below the predetermined range, the replenisher had theinferior storage stability.

The replenisher made from the mixture solution of hexafluorozirconicacid and zirconium nitrate described in paragraph [0033] of PatentLiterature 3 (JP 4996409 B) has the ratio M_(AC)/M_(F) of 0.33 and couldnot achieve the desired effect, as being apparent from ComparativeExamples 1 to 3 in Table 1.

In Comparative Examples 4 to 6, presumably because as anions thatstabilize zirconium in the replenisher, anions derived from the acidcomponent (C) are present at the higher rate than fluorine derived fromthe fluorine-containing compound (B), after the replenisher of any ofComparative Examples 4 to 6 is added to the metallic material surfacetreating solution, coordination between zirconium and other anionsbecomes stronger than Zr—F coordination in the metallic material surfacetreating solution, whereby stabilization of coating reaction becomesdifficult. It is presumed that this was affected by coordination betweenzirconium ion and F ion since hydrolysis of H₂ZrF₆ is utilized ascoating reaction.

1. A replenisher used to replenish metallic material surface treatingsolution with zirconium ion, the metallic material surface treatingsolution containing zirconium ion and fluorine ion and being used toform a chemical conversion coating containing zirconium on/over ametallic material through chemical conversion treatment and/orelectrolysis treatment, the replenisher comprising: a fluorine-freezirconium compound (A) containing at least one selected from a groupconsisting of zirconium basic carbonate, zirconium carbonate, zirconiumhydroxide and ammonium zirconium carbonate; a fluorine-containingcompound (B) containing at least one selected from the group consistingof hydrofluoric acid, a salt of hydrofluoric acid, hexafluorozirconicacid and a salt of hexafluorozirconic acid; and an acid component (C)containing at least one selected from the group consisting of nitricacid, hydrochloric acid, sulfuric acid and acetic acid, whereinfollowing relationships (I) to (III) are satisfied: (I) a ratio(M_(AC)/M_(F)) of a total molar quantity (M_(AC)) of anions derived fromthe acid component (C) with respect to a total molar quantity (M_(F)) offluorine ion derived from the fluorine-containing compound (B) is 0.35or more and less than 2.00; (II) a total concentration (g/L) ofzirconium ion derived from the fluorine-free zirconium compound (A) andthe fluorine-containing compound (B) is 25 or higher; and (III) a ratio(M_(F)/F_(Zr)) of a total molar quantity (M_(F)) of fluorine ion derivedfrom the fluorine-containing compound (B) with respect to a total molarquantity (M_(Zr)) of zirconium ion derived from the fluorine-freezirconium compound (A) and the fluorine-containing compound (B) is 2.00or more and less than 6.00.
 2. The replenisher according to claim 1,wherein the ratio (M_(AC)/M_(F)) exceeds 0.50 and is less than 2.00. 3.The replenisher according to claim 1, wherein the ratio (M_(AC)/M_(F))exceeds 0.50 and is 1.60 or less.
 4. A method for producing asurface-treated metallic material comprising: continuously performingchemical conversion treatment and/or electrolysis treatment on/over ametallic material in metallic material surface treating solutioncontaining zirconium ion and fluorine ion to form a chemical conversioncoating containing zirconium on/over the metallic material; andreplenishing the metallic material surface treating solution withzirconium ion by adding the replenisher according to claim 1 to themetallic material surface treating solution.
 5. A surface-treatedmetallic material obtained by the method for producing a surface-treatedmetallic material according to claim 4.